False online advertising of stock

I bought a treadmill on 15th May. There was more than enough stock available at the time. After six working days we realized that there was no movement when tracking the order. We then contacted makro to find out how far is the delivery only to find out that they do not have stock and the lady said she has no idea when they eventually will have stock again. So I decided to ask for a refund they told me it would take 10 working days. This is totally unacceptable because first of all you are busy with false advertising why do you advertise that there is stock available only to find out a few days later there is no stock. I want my money back as soon as possible. Just bought another treadmill at game in store at Woodlands with no hassle and they are delivering tomorrow.